To be honest, I think it's silly.
Firstly, the cost is absurd, compared to a screen protector for a phone.
Secondly, the film makes the whole watch look tacky, like a fake watch. It spoils the effects of brushed and polished surfaces and very obvious on watches like AP.
Thirdly, the film is applied in such a way that it likely only protects against abrasions and casual rubbing on surfaces. You can still damage corners and sides if you bang it against something hard like handrails.